Preserving wood



UNITED STATES PATENT OFFIC JOSEPH P. CARD, OF ST. LOUIS, MISSOURI.

PRESERVING WOOD.

SPECIFICATION forming part of Letters Patent No. 254,274, dated February .28, 1882.

Application filed June 15, 1881. (No specimens.)

To all whom it may concern:

Be it known that I, JOSEPH P. CARD, of St. Louis, Missouri, have made a new and useful Improvement in Preserving Wood, of which the following is a full, clear, and exact description.

Wood when impregnated with a soluble antiseptic, such as chloride of zinc, while remaining sound at the center, is apt to decay at and near the surface. Railway-ties, for instance, which have been treated with chloride of zinc, and then laid in atrackway, decay at and near, and sometimes to a depth much beneath, the surface where they come in contact with the ground. On the other hand, wood treated with oil remains sound even to the surface. The oil treatment, however, is much more expensive than the soluble antiseptic, and to that extent undesirable.

Attempts have been made to combine the advantages of the two treatments by applying the soluble antiseptic to the interior of the wood and the oil to the outside of the wood. For instance, wood has been inclosed from the outer air in a vessel, and a soluble antiseptic introduced into the wood. Then, without relieving thepressure upon it, the wood has been subjected to tar or bituminous oil. The effect, so far as the oil is concerned, is to confine its application practically to the outside of the wood. It may enter endwise into the pores A somewhat, but so far as the lateral surfaces of the wood are concerned the application is virtually nothing more than painting or coating them with oil, and insufficient for the preservation of wood.

To provide an improved mode of preserving wood when both a soluble antiseptic and an oil treatment are employed, and one by which the entire interior of the wood can be impregnated with a soluble antiseptic or mineral salt, and in conjunction therewith the entire outer portion from end to end of the various pieces, and to beneath the surfaces to a depth varying from, say, an eighth or tenth of an inch inward to, but not into, the central portion of the wood, especially in such forms of wood as railway-ties, long timbers, and piles, can be filled with oil, and one by which the introduction of the oil into the wood to beneath the lateral surfaces can becontrolled and directed to the desired depth, is theaim of the present improvement, which consists substantially as follows: First, in impregnating the entire wood with a soluble antiseptic, then removing the moisture from the entire outer portion of the wood to beneath the surfaces, (lateral as well as end,) to a depth varying from about an eighth or tenth of an inch in ward to, but not into, the central portion of the wood, to effect which removal the wood must meanwhile be relieved from or be free of any pressure which operates to retain the moisture within the wood, and then introducing the oil or other moisture-repellent intoand throughout such outer portion of the wood from whence the moisture has been'removed.

Zinc chloride is the antiseptic preferably used, and the oil is one that vaporizes above the boiling-point of water, and preferably creosote dead-oil.

The wood, either with or without preliminary steaming, is treated in theusual manner with the soluble antiseptic, taking, by weight, about two parts of chloride of zinc to ninetyeight parts of water. After this solution has been injected into the wood-and the more thoroughly it is injected the better the result-the moisture is expelled from or got out of the entire outer portion of the wood above described, during which stage of the operation the Wood must be free of any pressure, hydrostatic or gaseous, which would prevent the moisture from leaving said outer portion of the wood, and for this purpose the preferable practice is to open the vessel in which the wood is,

being treated to the open air. The removal of the moisture is hastened by the application of heat to the wood. The oil is then applied to the wood, preferably in a heated state, the preferable degree of heatbein g270 Fahrenheit. The heat of the oil also serves to expel the moisture from beneath the surface of the wood, especially from beneath the lateral surfaces, for in practice the heat passes transversely into the wood, heating the wood all along between its ends, and between the ends of the pores, to beneath the surface, and driving the moisture out therefrom the entire length of the wood, and, according to the duration of the operation, to any desired depth beneath the lateral surfaces. The heat passes transversely through the pores into the wood, but the moisture is expelled longitudinally through the pores to the outer ends thereof, and thus out of the wood. The oil then can and does enter beneath the entire surface of the wood and into and throughout the entire outer portion of the wood from which the moisture has been expelled.

In practice I do not need to heat the wood between the introducing of the soluble antiseptic and the subsequent application of the oil. The oil is applied hot, as stated, andsufficiently so to vaporize the moisture within the wood; but while the moisture is being thus vaporized the wood must be free of any pressure which would prevent the moisture from leaving the wood. After the moisture is removed the usual hydrostatic pressure is produced within the vessel, and the oil forced into the wood. In place of employing hydrostatic pressure in the final introduction of the oil into the wood, the oil may be introduced therein by means ofa vacuum formed within the wood.

I claim- 1. The herein-described mode of preserving wood, which consists in imprcgnatingthe wood with a solution of a mineral salt or a soluble antiseptic, then removing the moisture from the entire outer portion of the wood to beneath the surfaces, (lateral and end thereof,) the wood meanwhile being free of any pressure operat ing to retain the moisture in such outer portion, and then introducing the oil or other moisture-repellent into and throughout such outer portion, substantially as described.

2. Woodimpregnated throughout withamineral salt or soluble antiseptic, and its entire outer portion, including its lateral as well as end surfaces, and to beneath such surfaces to a depth varying from about an eighth or tenth ofan inch inward to, but not into, the central portion of the wood, with oil or other moisture-repellent.

JOS. P. CARD.

Witnesses:

0. D. MOODY, BRANDT V. B. DIXON. 

